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Date:   Mon, 25 Jul 2022 08:42:59 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Ming Lei <ming.lei@redhat.com>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
        ZiyangZhang <ZiyangZhang@linux.alibaba.com>,
        Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 1/2] ublk_drv: store device parameters
Message-ID: <20220725064259.GA20796@lst.de>
References: <20220723150713.750369-1-ming.lei@redhat.com> <20220723150713.750369-2-ming.lei@redhat.com>
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On Sat, Jul 23, 2022 at 11:07:12PM +0800, Ming Lei wrote:
> One important goal of ublk is to provide generic framework for
> making one block device by userspace.
> 
> As one generic block device, there are still lots of parameters,
> such as max_sectors, write_cache/fua, discard related limits,
> zoned parameters, ...., so this patch starts to store & retrieve
> device parameters and prepares for implementing ctrl command of
> SET/GET_DEV_PARAMETERS.
> 
> Device parameters have to be stored somewhere, one reason is that
> disk/queue won't be allocated until START_DEV command is received,
> but device parameters have to setup before starting device.

This seems rather overeingeering and really hard to read.  Any reason
to not simply open code the parameter verification and application
and do away with the xarray and all the boiler plate code?